Electrical plug device



Nov. 6, 1934. P CLARK, JR 1,979,958

' ELECTRICAL PLUG DEVICE Filed .April 13; 1952 3 Sheets-Sheet 1 nvenfor/7 /4 www Q Ceo/0kg@ Gttomeg NIWe 6, E934., P, CLARK, JR 1,979,958

ELECTRICAL PLUG DEVI CE Filed April 15. 1952 3 Sheets-Sheet 2 NOV, 6,934. A P, CLARK, JR 1,979,958

ELECTRICALl PLUG DEVICE Filed April 13, 1932 3 Sheets-Sheet 3 SnnentorGttorneg Clim/Jagt.

Fammi APatented Nov. 6, 1934 UNITED STATES PATENT lOFFICE The presentinvention relates to improvements in electrical plug devices, and hasfor an object to provide in such a device a plug and. Contact unit whichmay be formed of onepiece of metal, will be inexpensive and reliable inconstruction, and will provide a positive, nrm, and reliable contact. Afurther object is to provide a construction in which the plug contactunits may be assembled with great facility and will be *securely held inthe insulating housing against displacement and distortion. Anotherobject is to provide a housing which may be conveniently molded, andwhich will have the desirable characteristics of light weight,compactness and strength, and which will atthe same time provide ampleroom for the convenient attachment of wires. A

With the above and other objects in view embodiments of the inventionare shown in the accompanying drawings, and these embodiments will behereinafter more fully described with reference thereto, and theinvention will be finally pointed out in the claims.

In the drawings:

Fig. 1 is a side elevation of an electrical plug device, embodying theinvention, and showing in dot-and-dash lines another plug deviceinserted therein.

Fig. 2 is a planview of the device.

Fig. 3 is a vertical sectional view, taken along theline 3-3 of Fig. 1.

Fig. 4 is a vertical sectional view, taken alng the line 4 4 of Fig. 3.

Fig. 5 is a perspective view of the plug and resilient contact unit,accordingto the invention. Fig. 6 is a side elevation of the insulatinghousing employed.

Fig. 7 is a plan view of the insulation housing.

Fig. 8 is a plan view of the closure plate employed.

Fig. 9 is a lplan view of an insulating housing, employed in a modiedform of the invention.

Fig. 10 is a plan view of the closure plate employed with the housing asshown in Fig. 11.

Fig. 11 is a vertical sectional view of the modified form of theinvention employing the housing and cover plate shown in Figs. 9 and 10.

Fig. 12 is a side elevation thereof.

Fig. 13 is a side elevation turned 90 from the side, as shown in Fig. 9,and with the Closure plate removed.

Fig, 14 is a perspective view of the clamping ring employed in themodification shown in Figs. 9 to 13.

Fig. 15 is an elevation of-a portion of an insu-t lation housing similarto thatshown in Fig. 13, but with a modied form of clamping lug.

Fig. 16 is a fragmentary perspective view of a modified form of clampingring for cooperation e0 with the lug illustrated in Fig. 15.

Fig. 17 is a top plan view; partially broken away, of an electrical plugdevice according to a further modified form of the invention.

Fig. 18 is a side elevation thereof.

Fig. 19 is a side elevation, turned 90 from the side as shown in Fig.18.`

Fig. 20 is a top plan viewof the insulating housing employed. Y

Fig. 21 is a sectional view, taken along the line 21-21 of Fig. 19, andshowing in dot-and-dash lines another plug device inserted therein.

Fig. 22 is a perspective viewof the plugandl resilient Contact u'nitemployed in the modication illustrated in Figs. 17 to 21.

Fig; 23 is a plan view of the closure ployed.

Similar reference characters indicate corresponding parts throughout theseveral figures of the drawings. Y

Referring to the drawings, the insulating housing or shell of the plugdevice, according to the embodiment of the invention illustrated inFigs. 1 to 8, is preferably molded from hard rubber, bakelite, or othersuitable material, and is of generally cylindrical hollow form,comprising a cylindrical side wall 10 and a base l1, the side wallhaving at its upper end an outwardly onset cylindrical portion 12,connected to the main cylindrical portion 10 by an annular rib 13, whichalso serves the triple purpose of providing a ledge for protecting theedge of the clamping ring, a continuous annular reinforcement, and a:linger engaging'portion for enabling the plug to be convenientlyinserted or removed from a socket element. A lead Wire opening 14 isprovided in the side wall 10 extending downwardly from the upper edge,its upper end portionbeing spanned by the rib 13. -It will be observedthat the inner plate em wall of the portion 12 is substantially ush withthe outer surface-of the portion 10, so that in molding the housing' theopening 14 may be formed by a part on the mold core from which thehousing may be stripped by a straight pull.

A vertical partition wall 15 is provided within the housing shell in thecentral plane intersecting the center of the-lead wire opening, a

lead wire cut out 16 being provided therein adjacent the opening 14. Theedge of this cutout is designed so that it may. also be formed by aPOLQIL Qi the mold core and will not interfere with the 4stripping ofthe housing shell from the core by a straight pull. The upper edge ofthe portion 12 is provided with a series of projections 17 forinterlockingly engaging cutouts in the closure plate, as willhereinafter more fully appear. Upon the outer side of said portion 12there is formed a single narrow, slightly projectthread 18 of theportion 12.

In assembling the plug and contact unitsthe ing, large pitch screwthread 18. The arrangement of this thread in relation to the vrest ofthe housing structure lis such that it will not interfere with thestripping of the housing shell from the mold by a straight' pull, thematerial being suiciently elastic at the moment of stripping to permitthis.

In the base 11 there is provided in the compartment at each side of thepartition Wall 15 a relatively thick platform portion 19, having arectangular recess 20 therein and in the base of which is formed a plugreceiving slot 21. The side walls of the recesses 2t are beveled at theupper portions, as at 22, for guiding the contact portions of the plugand contacting units therein, and the exterior edges of the slots 21 arebeveled, as at 23, to guide the entrance of plugs therein.

A pair of plug and contact devices or units are secured in theinsulating housing, and each is preferably formed by bending a strip ofsuitable metal upon itself, as at 24, to form a double thicknesssubstantially rigid plugging portion 25, the two legs being bowedoutwardly at the base of the plugging portion, as at 26 and 27, andextended in converging relation to form contact portions 28 and 29. Thebowed portions 26 and 27 provide spring ends for the contact portions 28and 29, so that they may be sprung apart into parallel plug contactingrelation, without bending them between their ends, the spring actiontakingplace in thejbowed portions. The ends of the contact portions 28and 29 are iiared outwardly, as at 30 and 31, to provide plugguidingsurface's. The plugging portion 25 is provided adjacent the bowedportions 26 and 27 with an extended threaded hole 32 inv which a bindingpost screw 33 is screwed. In forming the extended threaded hole the sideleg at the head side ofthe screw is punched with a hole slightly largerthan the screw and the other side leg is pierced and extended and theopening therein threaded.

The plugging portion 25 is provided near its upper end with a hole 34,and the contact portions 28 and 29 are provided with inwardly pressedbosses 35 and 36 respectively, which are adapted to snap into the hole34 of a similar plug unit when the latter is plugged into the device, asshown in Fig. 1.

The cover plate 37 is provided with a pair of slots 38-38 'in linewiththe slots 21-21 in the base, and in its periphery there is provided aseries of cutouts 39 adapted to interlockingly engage the projections 17at the upper edge of the housing shell. The cover plate is clamped downupon the housing shell byvmeans of a threadedy engaged with theplugging'portio'ns 2.5-V are insertedthrough the slots'38--38 oi "thecover plate in which they preff'er'alrllyl 'engage wth'a snug-fit,andthe contaci-[portionsk are then placed in the housing at theyrespective sides ,of lthe y `partition walll l5, the fiaredends'Ofand 31being engaged in the rectangularfpockets R20-20;* 'The cover 'plate isthereuponclamped'in'place by the clamping ring Y@1o-s @timeagira matarlato the units before they are inserted in the housing. It will beobserved that the pockets 20-20 position the units vertically while atthe same time permitting the contact portions 28-29 to be separated uponinsertion of a plug between them, as shown in dot-and-dash lines in Fig.l.

In Figs. 9 to 14 I have illustrated a modification, similar in 4generalarrangement to the form illustrated in Figs. 1 to 8, but in which thehousing shell 10a is provided at its upper end with a series of lugs 41projecting upwardly and also projecting laterally and extending for ashort distance downwardly upon the outer surface. The under side 42 isslightly inclined to form the projection into a wedge, and at the lowerend of the incline there is provided a stop lug 43.

The closure plate 44 is provided with slots 45-45 in alignment with theslots 21-21 of the base, and at its periphery is provided with cut outs46 adapted to interlockingly engage the lugs 41 of the housing shell. Aflanged clamping ring 47 having an outer vertical side and upper andlower laterally disposed flanges is provided in its lower ange with aseries' of cutouts 48 adapted to be engagedover the lugs 41 and uponturning of the ring to have one end brought into wedging engagement withthe inclined under surface 42 of the lugs to thus clamp the closureplate in place, the stop lug 43 limiting the turning of the ring. A cutout 49 in the side and bottom flange registers with the lead wireopening 14 in the clamped position of the ring.

In the modification illustrated in Figs. 15 and 16 the under surface ofthe lug 41a is corrugated, and the lower flange of the ring 47 isprovided with a pressed in boss 50 adjacent the end of the cut out 48for yieldingly engaging the corrurgations, the stop lug 43a limiting theturning of the ring.

In Figs. 17 to 23 I have illustrated a further modification of theinvention comprising an insulating cup-shaped housing shell 51, the sidewall of which is cylindrical at its upper'portion and contracted towardthe base so that it may be conveniently gripped by the fingers. A post52 is integrally formed centrally of the base, its upper end beingslightly below the upper edge of the side wall, and reinforcing andguide walls 53 and 54 extend in opposite directions from opposed sidesof the post to the side wall. Diametrically opposed cut outs 55 and 56for lead wires are provided in the upper end of the side wall, andcutouts 57 and 58 are provided in the upper ends of the walls 53 and 54for extending lead wires from the binding posts to said openings 55 and56.

The side wall is provided adjacent the walls 53 and 54 with verticallydisposed channels 59 and 60, extending downwardly from the top edge andterminating in laterally disposed shoulders or ledges 61 and 62respectively.

Within the base and at opposed sides of the post 52 there are providedslots 63 and 64, disposed at right angles to the walls 53 and 54.

A pair of plug devices or units are secured in the housing, and eachv ispreferably formed by bending a strip of suitable metal upon itself, as

`portion, as' at'67 `and'68,`to form a shoulden'and extended inslightlyconverging relation, as at' `69'and 70 tojform contact portions.

portions 4 4 contact portions 69: and7p, sorthat they'may be The bowed A67 andV 68 provide spring" ends for the sprung apart Without bendingthem between their4 ends, the spring action taking place in the bowedportions. The contact portion 69 is bent laterally, as at 71, and isprovided with an extended threaded hole 72 to receive a binding postscrew 73, and the other contact portion 70 is ared at its ends, as at70a to provide a plug guiding surface.

The plugging portion 66 is provided near its upper end with a hole 73,and the contact portions 69 and` 70 are provided with inwardly pressedbosses 7474 respectively, which are adapted to snap into the hole 73 ofa similar plug unit when the latter is plugged into the device, as shownin dot-and-dash lines in Fig. 21. The guide walls 53 and 54, whichextend to the closure plate 76 adjacent the slots 80 and 81 eachprovides a guide to insure properly aligned insertion of the plugging'portions.-

In assembling the units the plugging portions 66 are projected throughthe slots 63 and 64 in the base of the housing, the shouldered portions67-68 abutting the base -at the inner side, and a depressible finger 75formed on one of the legs of the plugging portion engaging at the outerside to thus retain the unit against displacement and accidentalremoval. It will be understood that in inserting the unit the finger 75will be depressed as it passes through the slot and will snap intolocking relation when the unit is fully in serted. The laterally bentportions 7l are engaged in the channels 59 and 60 upon the ledges 61 and62 in'such relation as to position the unit, while at the same timepermitting a slight out- Ward and inward sliding movement of saidportions 71, as plugging ends are engaged with and disengaged from thecontact portions 69 and 70.

A cover plate 76 is seated within the open end of the housing upon theupper end of the post 52 and is provided with projecting lips 77 and 78which engage the lead wire openings, the lead wire openings preferablyhaving ledges 79-79 upon which the lips rest. Plug receiving slots 80and 81 are provided in the plate in line with the slots 63 and 64 of thebase, and a center hole 82 is provided between them -in which thesecuring bolt 83 is engaged, this bolt being extended through a passage84 in the post 52, and having a nut 85 upon its threaded end disposed ina countersunk recess 86 in the lower end of the post. I have illustratedand described preferred and satisfactory embodiments of the invention,but it will be obvious that changes may be made therein, within thespirit and scope thereof, as dened in the appended claims. v

Having thus described my invention what I claim and desire to secure byLetters Patent is:-

1. In an electrical plug device, a housing of insulating material havinga plug receiving opening, and a metallic plug and resilient contact unitcarried in said housing, comprising a single strip of metal bent uponitself for a portion of its length to form a double thickness plugportion adapted to project from said housing the two sides of said stripbeing bent outwardly adjacent the base of said double thickness plugportion symmetrically at each side of the central plane of said plugportion to form outwardly movable springy portions and being extendedfrom said springy portions to form a pair of single thickness contactportions, said contact portions being disposed in relation to said plugreceiving opening to receive a plug between them.

2. In an electrical plug device, a housing of insulating material havinga plug receiving opena pair of single thickness extensions integral withsaid double thickness plug portion and forming opposed resilient contactportions, one side of said double thickness plug portion having athreaded opening within the housing and the other side having an openingaligned with said threaded opening and a headed lead wire attachingscrew carried by said double thickness plug portion engaged through saidlast mentioned opening and screwed into said threaded opening adapted tosecure the two sides of said plug portion together, said contactportions being disposed in relation to said plug receiving opening toreceive a plug between them.

- 3. In an electrical plug device, a housing of insulating materialhaving a plug receiving opening, and a metallic plug and resilientcontact unit carried in said housing comprising a single strip of metalbent upon itself for a portion of its length to form a double thicknessplug portion adapted to'pr'oject from the end of said housing and a pairof single thickness extensions longitudinally aligned with said plugportion and forming opposed resilient contact portions, said contactportions being disposed in relation to said plug receiving opening toreceive a plug between them, one of said portions being extendedlaterally to provide a lead wire attaching means.

1 4. A metallic -plug and resilient contact unit for use inan-electrical plug device having a plug receiving opening, comprising asingle strip of metal bent upon itself for a portion of its length toform a double thickness plug portion and a pair of single thicknessextensions integral with said double thickness plug portion vand formingopposed contact portions adapted to receive a plug inserted in said plugreceiving opening between them, the two sides of said strip being bowedoutwardly between said double thickness plug portion and said singlethickness contact portions to form springy portions.

5. In an electrical plugV device, a cup shaped housing of moldedinsulating material having a side wall including an outwardly offsetcircumferentially continuous collar portion adjacent its upper end, anannular shoulder upon the inner surface of said side wall formed by theoffset of said collar portion there being a lead wire opening in theside wall below said collar portion, said opening having non-convergingsides extending to said shoulder and being vertically clear and entirelyinwardly disposed with respect to the inner surface of said collarportion, and metallic contact units within said housing.

6. In an electrical plug device, a housing of insulating material havinga plug receiving opening, and a metallic plug and*1 resilient contactunit carried in said housing comprising a single strip of metal bentupon itself for a portion of its length to form a longitudinallyextending double thickness relatively stiff plug portion adapted toproject from,said housing and a pair of longidinally extending singlethickness extenresilient contact portions, said contact portions beingdisposed inrelation to said plug receiving opening to receive a plugbetween them, the plug said double thickness plug portion disposedsymmetrically at each side of the central plane of said plug portion andforming opposed contact portions adapted to receive a plug inserted insaid plug receiving opening between them, the plug receiving spacebetween said contact portions being longitudinally -aligned `with saidplug portion whereby the corresponding plug portion of an identical plugdevice may be engaged therewith. Y

' LANCASTER P. CLARK, JR.

Y. L .150v f DISCLAIMER 1,979,958.Lancaster P. Omrk, Jr., Fairfield,Conn. ELECTRICAL PLUG DEVICE. Patent dated November 6, 1934:. Disclaimerfiled March 13, 1941, by the assignee, Elecmc Pug, Inc. Hereby entersthis disclaimer to Claims l, 4, 6, and 7 in said speeiflcaton,

[Ofic/al Gazette April 8, 1941.]

